In the 3G cellular telephony system known as WCDMA, Wideband Code Division Multiple Access, the system is divided into cells, and has a number of nodes known as Radio Base Stations, RBS, each of which monitors and controls traffic to and from one of the cells. The system also comprises a node “above” the RBSs, known as the Radio Network Controller, RNC, with one of the functions of the RNC being to monitor and control the RBSs.
The traffic from the RBSs to the RNC can be expressed as a number of flows. Accordingly, the system needs to comprise a function for monitoring and controlling the flows from the RBSs to the RNC. The purpose of this monitoring and controlling is, inter alia, to avoid congestion over the interface between the RBSs and the RNC, and also over the interface between the RNC's in the system.
Previously known such functions for monitoring and control of the traffic from the RBS to the RNC have been so called aggregated functions, i.e. they work on an aggregation of flows between the RBS and the RNC.
Aggregated control functions have a number of disadvantages, for example the following: Aggregated flow control solution can work well when all flows from the RBSs to the RNC encounter a common bottleneck. However, when different bottlenecks occur in the system, such as if the interface between RNC's becomes a bottleneck, an aggregated solution does not work particularly well.